Heating, ventilation and air-conditioning (HVAC) systems regulate a number of environmental conditions in homes, offices, factories, warehouses, and vehicles. These HVAC systems may include one or more HVAC units to move, cool, or heat air. A thermostat may connect to the HVAC units over a communications network, to provide control to the HVAC units. One or more devices in the HVAC may connect to a server. Allocating bandwidth and authenticating HVAC devices presents a number of problems when using a server to connect with HVAC systems.